Domestic Heat Loss Calculator UK

Heat Loss Formula:

\[ \text{Heat Loss} = U \times A \times \Delta T \times 24 \text{ (kWh/day)} \]

Heat Loss:

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1. What is Domestic Heat Loss?

Domestic heat loss refers to the amount of heat energy that escapes from a building through various surfaces and components. Understanding heat loss is crucial for energy efficiency, heating system design, and compliance with UK building regulations.

2. How Does the Calculator Work?

The calculator uses the standard heat loss formula:

\[ \text{Heat Loss} = U \times A \times \Delta T \times 24 \text{ (kWh/day)} \]

Where:

\( U \) — U-Value (W/m²K) - Thermal transmittance of the building element
\( A \) — Area (m²) - Surface area of the building element
\( \Delta T \) — Temperature Difference (°C) - Difference between indoor and outdoor temperatures
\( 24 \) — Hours in a day for daily energy calculation

Explanation: The formula calculates the daily heat energy loss through a specific building element based on its thermal properties, size, and the temperature gradient.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculation is essential for proper heating system sizing, energy efficiency assessments, building regulation compliance, and reducing energy costs in UK homes.

4. Using the Calculator

Tips: Enter U-value in W/m²K (typical values: walls 0.18-0.35, windows 1.2-2.8), area in square meters, and temperature difference in °C (typical UK design temperature difference: 20-25°C).

5. Frequently Asked Questions (FAQ)

Q1: What are typical U-values for UK buildings?
A: For new builds: walls 0.18 W/m²K, floors 0.15 W/m²K, roofs 0.13 W/m²K, windows 1.4 W/m²K. Existing buildings have higher values.

Q2: How does this relate to UK building regulations?
A: Part L of Building Regulations sets maximum U-values for different building elements to ensure energy efficiency compliance.

Q3: What temperature difference should I use?
A: For design purposes, use 21°C indoor minus the local design external temperature (typically -1 to -3°C in UK), giving ΔT of 22-24°C.

Q4: Can I calculate total building heat loss?
A: Yes, calculate heat loss for each building element (walls, windows, roof, floor) separately and sum them for total building heat loss.

Q5: How accurate is this calculation?
A: This provides a good estimate for steady-state conditions. For more precise calculations, consider air infiltration, thermal bridging, and dynamic conditions.